1. Field of the Invention
The present invention relates to a crank cover assembly for a bicycle, and more particularly, to a combination of a pre-molded shell and a pre-molded leaf for covering a bicycle crank.
2. Description of the Related Art
In forming a prior art bicycle crank, the crank is first molded through metal casting or forging. The crank itself is molded to a specified shape, color, and luster. As shown in FIG. 6, crank A having a shaft hole A1 and a threaded hole A2 at longitudinally opposed ends thereof, and having the desired shape is thus formed. To vary the crank color and the overall appearance of the bicycle, a plastic outer coat is formed onto prior art cranks after they have been forged. The plastic outer coat is molded in the mold holding the forged metal crank. In practice, this process is plagued by the following shortcomings:
1. During molding, burn marks are often formed on the shaft hole and the threaded hole of the crank. Great time and effort are expended to individually scrape out those marks. Consequently, the production process is rendered complex and inefficient, and production costs are increased. PA1 2. The crank is first formed by forging before the plastic outer coat is formed thereon by molding. The covering plastic coat may only be formed after the forging process is completed. Thus, production of the entire crank unit consumes much time, and inefficient productivity results. PA1 3. Due to the weight of a metal crank and relatively low strength of plastic in the molding, damage to the plastic outer coat tends to result quite readily during removal of the crank from the mold. PA1 4. If the configuration of the plastic outer coat or crank is to be changed, the mold must also be changed, causing the process to exhaust much time and increase production costs.
In view of the above-mentioned and other shortcomings of conventional plastic coated cranks, the object of the present invention is to provide a process that separates the crank forging and plastic molding processes to prevent the unnecessary consumption of resources and occurrence of errors in the molding process, while providing a convenient means by which to change a given crank's appearance.